Recent advances in silicon-based nanostructures for thermoelectric applications

Abstract

In this work, implementations of silicon-based thermoelectric nanomaterials are reviewed. Approaches ranging from nanostructured bulk—i.e., macroscopic materials presenting nanoscale features—to more complex low-dimensional materials are covered. These implementations take advantage of different phonon scattering mechanisms and eventual modifications of the electronic band-structure for the enhancement of the thermoelectric figure of merit. This work is focused on the recent advances in silicon and silicon-based thermoelectric nanomaterials of the last decade—at both the theoretical and experimental level—with the spotlight on the most recent works. Different nanostructures and their fabrication methods are detailed, while the thermoelectric performances and the feasibility of their integration into functional micro-harvester generators are compared and discussed. This Research Update first covers the advances in nanostructured bulk, such as nanometric-sized polycrystals or defect-induced materials. Subsequently, it reviews low-dimensional materials, namely, thin films and nanowires. Later, other complex structures based on nanoporosity, superlattices, or core–shell schemes are detailed. Finally, it is devoted to present examples of the successful implementation of nanostructured silicon into functional thermoelectric devices.